This invention relates generally to detectors, and more specifically to a system and a method for detecting a malfunction in a magazine spooling machine of the type that assembles end caps to a film magazine.
It is well known in the photographic industry to provide cylindrical film cans or magazines having a first light-tight cap at one end and a light-tight mouth formed by axially extending, peripheral spaced-apart lips onto which plush material is secured in a facing relation. In the manufacture of such film magazines under darkroom conditions, a spool having a roll of unexposed light-sensitive film wound thereon is fed into the outer free end of each magazine with a leading end portion thereof extending through the light-tight mouth of the magazine. The magazine containing the film is positioned in a forming or capping jaw which compresses the outer free end of the magazine to the precise shape for receiving a second end cap. The second end cap is fed from an end cap source to a position in alignment with the magazine, and the second end cap is advanced by a staking mechanism onto or over the free end of the magazine. A portion of the staking mechanism is expanded, crimping the rim of the second end cap to the end of the magazine to form a completed light-tight film magazine. Problems have arisen in situations in which the first or the second end cap is, missing from the magazine, reversed in the feed to the assembly area, improperly staked, which results in a defective film magazine.
A patent of interest for its teaching of a mechanism for detecting a missing end cap is U.S. Pat. No. 3,802,052 entitled "Detecting Mechanisms for Detecting a Missing End Cap of a Film" by R. C. Andler et al, which patent is assigned to Eastman Kodak Company, the assignee of the present application.
The detector of that patent utilizes a pusher element which moves a predetermined distance into engagement with one end of the magazine. If the cap is correctly positioned the pusher is stopped; if the cap is missing or improperly set the magazine is ejected.
In some instances, an improperly set cap may pass undetected because physically it is in a position that is considered to be correct.
The system and the method of the present invention senses the time it takes to position the end cap on the magazine. An interference will increase the time and a missing end cap will decrease the time. The staking process is also monitored using a similar system and method, which checks and final home and extended positions of staking fingers.
Error conditions that can be sensed by the present system and method include backward caps, bent caps, bent magazines, no cap, spools staked under, misaligned parts, oversized caps, and faulty machine hydraulics. Also, the present system and method can indicate trends which are related to part wear. For example, if times for assembly start to increase gradually over a large number of parts it tends to show that some part of the assembly machine is beginning to wear and possibly should be replaced.